Specifications
39
If you frequently encounter QRM in SSB modes, use the 2.9 kHz selection; this
will insert FL2 when the normalized passband width is used (NORM switch). If
QRM is less of an issue or you frequently use ESSB, use the 2.4 kHz selection
(original value); this will insert FL1 at the NORM setting. The PBT knob can
override either selection (see below). To select the desired FL2 insertion point:
Tap ‘1’ to select either 2.4 or 2.9 kHz using the criteria above.
Note on SSB demodulation methods used for FL1 vs. FL2: When FL1 is in
selected (wide filter), the KX3 uses conventional SSB demodulation, providing
the best overall audio fidelity. When FL2 is selected (3 kHz filter), the KX3 uses
“Weaver” SSB demodulation, which introduces a narrow 1.5 kHz notch into the
receive passband as part of the DSP algorithm. This notch typically has no impact
on speech intelligibility, but it can sound slightly different to an operator who is
most concerned about fidelity.
PREAMP
20 dB
Sets preamp gain to 10, 20, or 30 dB on a per-band basis. (30 dB is typically
used only on 6 meters, where it improves sensitivity by 1-2 dB. This setting
should only be used if necessary, since it increases susceptibility to overload.)
There are actually two preamps: the 20 dB low noise amp (LNA) and the 10 dB
setting of the isolation amp (see RX ISO, below). Use the 20-dB preamp when
possible, since it has a better noise figure and lower current drain. If you select 10
or 30 dB, the isolation amp is turned on, adding about 15 mA to current drain.
REF CAL
114.nnn.nn
Used to calibrate the KX3’s synthesizer; normally this is done at the factory. VFO
A is used to set the reference frequency (typically 114.2-114.4 MHz). Refer to pg.
31 for calibration details.
Note: If the menu name is REF*CAL, then an extended VFO temperature
compensation procedure has been performed. This may be helpful when JT65,
WSPR, or other modes are used with the KX3, especially on the higher bands. If a
KX3-2M module is installed, the extended proceure must be used (unless only
FM operation is planned). Instructions can be found on our website. A
temperature-stable RF source operating near 50 MHz is required, such as an
Elecraft XG50 crystal oscillator.
RPT OFS
600
Sets the transmit offset (in kHz) for repeater operation, from 0 to 5000 kHz.
Stored per-band and per-memory. Use ALT to select +/- offset or simplex.
RS232
4800 b
RS232 (or USB) communications rate in bits per second (bps). During firmware
download (via the KX3FW PC program), the baud rate is set automatically to
38400 baud, but it is then restored to the value selected in this menu entry.
RX EQ
--------
(+0 dB,
each
band)
Receiver audio graphic equalizer. VFO A is used as an 8-band bar graph, showing
boost or cut (- 16 dB to +16 dB in 1 dB increments) for each AF band. The 8
bands are 0.05, 0.1, 0.2, 0.4, 0.8, 1.6, 2.4 and 3.2 kHz. Tap 1 -8 to select an AF
band. VFO A selects boost/cut. Hold CLR to reset all bands to +0 dB.
CW and voice mode RX EQ are separate. Not applicable to DATA modes.
RX I/Q
OFF
Set to ON to use the KX3’s RX I/Q jack with SDR (software-defined radio)
applications (pg. 26).
RX ISO
OFF
Set to ON if you’re using the KX3 nearby other receivers operating on the same
band, and a strong carrier from the KX3 is heard when its VFO is tuned to the
same frequency as the other receiver’s. The isolation amplifier is between the
antenna jack and the mixer, preventing leakage from the KX3’s local oscillator.